Molality is defined as the number of moles of the solute particles which dissolved in unit weight of the solvent. It can be represented by the symbol m . m = Number of moles of solute Mass of the solvent ( in kg ) m = n B W A ( kg ) ∵ n B = W B M B m = W B M B × 1000 W A Where W B and W A are the mass of solute and solvent, respectively.

A sample of drinking water was found to be contaminated with CCl 4 . The level of contamination was 8 . 5 ppm by mass. (Molecular mass of CCl 4 = 153 . 18 g · mol - 1 ) (i) Calculate the contamination level in mass percent. (ii) Calculate the contamination level in molality

i 85 × 10 - 4 m % ; ii 0 . 55 × 10 - 4 m

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Earn 100

Calculate the molality of $2$ molar solution of urea having density $1.1 g / ml$ ?

Important Questions on Solutions

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Find molality of pure water

(H_{2} O = 18)

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Define: Molality

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

An antifreeze solution is prepared from

222.6 g

of ethylene glycol

(C_{2} H_{6} O_{2})

and

200 g

of water. Calculate the molality of the solution. If the density of the solution is

1.072 g {mL}^{- 1}

, then what shall be the molarity of the solution?

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Calculate the molality of

20 %

(by weight) potassium carbonate solution.

(K = 39, C = 12, O = 16)

HARD

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

A sample of drinking water was found to be contaminated with

{CCl}_{4} .

The level of contamination was

8.5 ppm

by mass. (Molecular mass of

{CCl}_{4} = 153.18 g \cdot {mol}^{- 1}

)
(i) Calculate the contamination level in mass percent.
(ii) Calculate the contamination level in molality

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Molality of

30 %

\frac{W}{W}

aqueous solution of

NaOH

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Define molality of a solution.

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

An antifreeze solution is prepared from

222.6 g

of ethylene glycol

(C_{2} H_{6} O_{2})

and

200 g

of water. Calculate the molality of the solution. If the density of the solution is

1.072 g {mL}^{- 1}

, then what shall be the molarity of the solution?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

Calculate molality of

1 M

concentrated solution of

{NaNO}_{3}

if density of solution is

1.25 g {cm}^{- 3}

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

3.65 gm HCl

is dissolved in 500 gram water. Determine the molality of the solution.

HARD

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

An antifreeze solution is prepared from

222.6 g

of ethylene glycol

(C_{2} H_{6} O_{2})

and

200 g

of water. Calculate the molality of the solution. If the density of the solution is

1.072 g {mL}^{- 1}

, then what shall be the molarity of the solution?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

3.0 g

of oxalic acid

[{({CO}_{2} H)}_{2} \cdot 2 H_{2} O]

is dissolved in a solvent to prepare a

250 mL

solution. The density of the solution is

1.9 g / mL

. The molality and normality of the solution, respectively, are closest to

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

In $214.2 g$ syrup of sugar, $34.2 g$ sugar ( $C_{12} H_{22} O_{11}$ ) is present. What will be the molality of sugar syrup? ( $C = 12, H = 1, O = 16$ ).

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

In a sample of drinking water, many impurities are found including chloroform, ${CHCl}_{3}$ , which are carcinogenic. The level of these impurities was $15 ppm$ (according to mass)

Find the molality of chloroform in this sample of water.

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

$4 g$ of Caustic soda (molar mass $40$ ) is dissolved in water and solution is made to $200 gm$ . Calculate the molality of the solution.

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

3.0

gram ethanoic acid in

50

gram benzene having _____ molality? (Atomic weights :

H = 1, C = 12, O = 16

HARD

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

To prepare a solution with molality of

0.1 mol {kg}^{- 1}

of ethanol in

100 g

of water, the mass of ethanol needed is (molecular weight of ethanol

= 46 g {mol}^{- 1}

)

EASY

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

2.82 gm

of glucose (Molecular mass= 180) is dissolved in

30 gm

of water. Calculate molality of the solution.

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

The density of

NaOH

solution is

1.2 g {cm}^{- 3} .

The molality of this solution is

m

(Round off to the Nearest Integer):
[Use : Atomic masses :

Na : 23.0 u O : 16.0 u

H : 1.0 u

Density of

H_{2} O : 1.0 g {cm}^{- 3}]

MEDIUM

Chemistry>Physical Chemistry>Solutions>Methods of Expressing Concentration of Solutions

3 \cdot 42 \times 10^{- 2} kg

Sugar (molar mass

342

) is dissolved in water to produce

234.2 g

of sugar syrup, what is the molality of sugar syrup ?

Calculate the molality of 2 molar solution of urea having density 1.1 g/ml?

Important Questions on Solutions

Learn and Prepare for any exam you want !

Calculate the molality of $2$ molar solution of urea having density $1.1 g / ml$ ?